This invention belongs to the field of synthetic organic chemistry and provides to the art a new series of antimicrobial heterocyclic compounds.
The 3-hydroxybenzo[b]thiophene-2-carboxylates which are starting compounds for the compounds of this invention were disclosed by Beck, J. Org. Chem. 38, 4086 (1973). Such compounds were first synthesized by Friedlander, Justus Liebigs Ann. Chem. 351, 390 (1906).
Additional references which relate to the synthesis of benzo[b]thiophenes include Wagner, U.S. Pat. No. 3,659,004, Roos, U.S. Pat. No. 3,663,568, and De Angelis, U.S. Pat. No. 3,706,747.
The background of this invention also includes the prior art synthesis of benzofurans with alkoxides as reagents. References on the synthesis include Friedlander, Chem. Ber. 32, 1867 (1899) and Schroeder et al., J. Org. Chem. 27, 586 (1962).
De Angelis, U.S. Pat. No. 3,706,747, disclosed benzothieno[3,2-d]pyrimidines and benzofuro[3,2-d]pyrimidines which are also relevant to the background of this invention.